Usually, i dictate Feb the 18th as the official birthday, but recent research showed that wechall got live on Feb the 12th 2008.

I will celebrate it the geek way, and redo what @Kender did years ago;
Come up with interesting statistics about wechall, it's users and the participating challenge sites...…

But this time, please provide ideas, queries and questions.

I do the start:

0) Which was the korean site(s) that joined with the largest userbase?
0) Which users did the most work / gained the most points (no score from linking)
0) How many valid solutions have been entered? (group by week and country?)
0) How many PM did @livinskull receive? and where is @paipai and @ch0wch0w?
0) Feb 12th+18th 2018 is party in one of the hackerspaces? ;)

I am sure we can come up with some interesting questions and stats,,,, and well...